This disclosure relates to polycarbonates, and in particular to polycarbonate-polysiloxane copolymer blends with polycarbonates and uses thereof.
Polycarbonates are useful in the manufacture of articles and components for a wide range of applications, from automotive parts to medical devices. Polycarbonates having a high percentage of units derived from 1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane (DMBPC) in particular have excellent attributes such as ammonia resistance, resistance to scratching, and water vapor and oxygen impermeability compared to other polycarbonates. At least in part because of these good barrier properties, such polycarbonates are useful in medical packaging applications. However, such polycarbonates are also brittle (of low ductility) compared to polycarbonates containing a high number of units derived from bisphenols such as bisphenol A. The addition of materials that can improve ductility, for example polydiorganosiloxane units, however, leads to increased haze in the compositions.
There accordingly remains a need in the art for polycarbonates that have improved ductility, together with other advantageous properties, such as oxygen impermeability, water vapor impermeability, scratch resistance, and/or improved transparency.